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Freyqq

macrumors 601
Original poster
Dec 13, 2004
4,038
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I have a relatively technical RAM question. I currently have 2 sticks of 4gb 1333mhz rated CL9 ram and 2 sticks of 2 gb 1066mhz rated CL7 ram. I am trying to decide which to put into a mid 2010 15" mbp. That mbp can only take up to 1066mhz ram I believe. If I put the 1333mhz ram in, will it downclock to 1066mhz and become CL7? Or, would it downclock to 1066mhz and remain CL9? I'm trying to decide which sticks of ram to use. Thanks!
 
I have a relatively technical RAM question. I currently have 2 sticks of 4gb 1333mhz rated CL9 ram and 2 sticks of 2 gb 1066mhz rated CL7 ram. I am trying to decide which to put into a mid 2010 15" mbp. That mbp can only take up to 1066mhz ram I believe. If I put the 1333mhz ram in, will it downclock to 1066mhz and become CL7? Or, would it downclock to 1066mhz and remain CL9? I'm trying to decide which sticks of ram to use. Thanks!


does the MBP take 8GB of ram? if so why take 4 less GB for some CL #?
 
my workload doesn't tax my system more than 4 gb, but if there is no speed decrease I'd upgrade because I have the RAM available.
 
my workload doesn't tax my system more than 4 gb, but if there is no speed decrease I'd upgrade because I have the RAM available.

even if it made your 2 sticks of 4GB the same speed as the 2 sticks of 2GB i dont see the disadvantage of putting the 2 sticks of 4GB in your machine if you already own the RAM
 
even if it made your 2 sticks of 4GB the same speed as the 2 sticks of 2GB i dont see the disadvantage of putting the 2 sticks of 4GB in your machine if you already own the RAM

If that were the case, then I agree. My original question, though, is whether there is a speed decrease between the two types of ram.
 
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If that were the case, then I agree. My original question, though, is whether there is a speed decrease between the two types of ram.

No. The 2010 MBPs use 1066 MHz RAM and will downclock the 1333 MHz RAM to 1066 MHz. So there will be no speed difference from one to the other in a 2010 MBP.
 
No. The 2010 MBPs use 1066 MHz RAM and will downclock the 1333 MHz RAM to 1066 MHz. So there will be no speed difference from one to the other in a 2010 MBP.

I know that, but what about the CAS latency (CL)? Does that change too?
 
I know that, but what about the CAS latency (CL)? Does that change too?

IIRC, no, because that is a physical characteristic of the RAM chip.

Why not just try both and see which works better?
 
IIRC, no, because that is a physical characteristic of the RAM chip.

I'm not sure if that's the case. I just did some research and it seems like, as you change clock speed, the CAS Latency varies as well. I think that's why all the 1333mhz ram on newegg is CL9 and all the 1066 ram on newegg is CL7. Can anyone confirm?
 
I'm not sure if that's the case. I just did some research and it seems like, as you change clock speed, the CAS Latency varies as well. I think that's why all the 1333mhz ram on newegg is CL9 and all the 1066 ram on newegg is CL7. Can anyone confirm?

So if someone agrees with you it's a confirmation? But the post you quoted is less valid

Pretty sure confirmations on these types of question are better done with research and testing not asking randoms
 
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